diff --git a/config/initializers/10-patches.rb b/config/initializers/10-patches.rb
index 28f4f3670..0e01e28a5 100644
--- a/config/initializers/10-patches.rb
+++ b/config/initializers/10-patches.rb
@@ -114,7 +114,7 @@ module DeliveryMethods
       dest_dir = File.join(Rails.root, 'tmp', 'emails')
       Dir.mkdir(dest_dir) unless File.directory?(dest_dir)
       filename = "#{Time.now.to_i}_#{mail.message_id.gsub(/[<>]/, '')}.eml"
-      File.open(File.join(dest_dir, filename), 'wb') {|f| f.write(mail.encoded) }
+      File.binwrite(File.join(dest_dir, filename), mail.encoded)
     end
   end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index c0eb0ba90..54dfaba9c 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -375,9 +375,7 @@ module Redmine
     def save_pdf
       assert_equal 'application/pdf', response.media_type
       filename = "#{self.class.name.underscore}__#{method_name}.pdf"
-      File.open(File.join($redmine_tmp_pdf_directory, filename), "wb") do |f|
-        f.write response.body
-      end
+      File.binwrite(File.join($redmine_tmp_pdf_directory, filename), response.body)
     end
   end
 
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index a870e3697..954c44269 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -362,9 +362,7 @@ class AttachmentTest < ActiveSupport::TestCase
     a = Attachment.find(20)
     assert a.disk_directory.blank?
     # Create a real file for this fixture
-    File.open(a.diskfile, "w") do |f|
-      f.write "test file at the root of files directory"
-    end
+    File.write(a.diskfile, 'test file at the root of files directory')
     assert a.readable?
     Attachment.move_from_root_to_target_directory